The present invention relates to a detector for detecting an object carried by a media item. In particular, the invention relates to a detector for detecting electrically conducting objects, such as staples or clips, carried by laminar media items such as checks, banknotes, and such like. The invention also relates to a self-service terminal, such as an automated teller machine (ATM), including a detector for detecting objects carried by media items.
In addition to dispensing cash, it is common for ATMs to receive deposits from users. These deposits typically comprise one or more checks and/or one or more banknotes. To validate the authenticity of these media items, it is conventional to image the front and rear faces of each media item using an optical imager in close proximity to or in contact with the media item.
If a user deposits a media item carrying an object, such as a staple, a paperclip, or such like, then this object may scratch the optical imager, thereby degrading the performance of the imager. This may result in the imager becoming completely inoperative, requiring a technician to visit the ATM and replace the imager. This incurs the cost of:                the ATM being out of service, at least for deposit transactions,        the technician visiting the ATM, and        a replacement imager.        
As many components within an ATM are electrically conducting, it is not feasible to use a metal detector to detect an object carried by a media item. Furthermore, as the object is generally small compared with the media item to which it is attached, it is difficult to detect the object as it is being transported within an ATM.